2. Field of the Inventions
The present invention relates to a cable marking apparatus which uses a laser marker to provide markings, such as alphanumeric characters and symbols, in an outer jacket of a moving cable and more particularly to a cable marking apparatus which also includes an applicator to apply a wax and a wax remover to remove the wax and enhance the readability of the markings.
2. Description of the Prior Art
After a cable which has an outer jacket with an outer surface has been manufactured, a cable marking machine applies markings to the outer jacket at predetermined intervals on the outer surface of the outer jacket. These markings are coded and indicative of the type and size of the cable. There are many different cable marking machines which use embossers, printers or laser markers. There are advantages in using laser markers in cable marking machines because the laser markers can provide cable marking machines with a high speed output. However, cable marking machines have not been able to effectively and fully utilize the laser markers. This is due to certain limitations, such as the number of digits which are required, the frequency of the markings and the lengthy set-up time required to mark cables of different types and sizes.
U.S. Pat. No. 4,370,542, entitled Cable Marking Method and Apparatus, issued to John B. Mills and Christopher H. Roberts on Jan. 25, 1983, teaches a cable marking machine which includes a computer and a laser marker and which marks a cable. The computer is a preprogrammed microprocessor and controls the operation and positioning of the laser marker. The cable has an outer jacket of insulation and an inner jacket of insulation. The color of the outer jacket of insulation is different from and contrasts with the color of the inner jacket of insulation. The laser marker burns at pre-determined intervals the outer jacket of insulation. The markings are rendered visible due to the contrasting colors of the inner jacket of insulation.
U.S. Pat. No. 4,808,966, entitled Laser-Markable Electric Cable, issued to Jean-Pierre Ferlier and Michel Marechal on Feb. 28, 1989, teaches an outer jacket and an inner jacket for use with a cable. The outer jacket is of a thickness in the range of 5 to 50 microns. The color of the inner jacket contrasts with the color of the outer jacket. A selected area of the outer jacket absorbs light energy from a laser marker during marking through its entire thickness and is completely vaporized so as to reveal the corresponding area of the inner jacket thereby rendering the markings visible. German Pat. No. 3,147,230 describes an outer jacket of a cable whose outer surface is initially sprayed with a colored coating which is of a specified color and which is baked using either radio-frequency energy or infra-red light energy. Light energy from a laser marker is subsequently used to selectively burn off the coating. The markings are rendered visible due to the contrasting colors of the outer jacket and the coating.
U.S. Pat. No. 4,720,618 and U.S. Pat. No. 4,727,235, both entitled Method and Apparatus for Equalizing Power Output in a Laser Marking System, issued to Michael E. Stamer and Stephen A. Kozich on Jan. 19, 1988 and Feb. 23, 1988, teach a laser marker which includes a computer, a monitor with a keyboard, a laser interface circuit, a direct current power supply, a plurality of radio frequency amplifiers and a laser head. The keyboard of the monitor permits the operator to communicate with the computer in order to enter data and alter the operation of the laser interface circuit. The laser marker inscribes a matrix of a plurality of dot-craters to form alphanumeric characters and symbols onto moving articles. The laser marker may be adapted to apply markings to a cable.
U.S. Pat. No. 4,652,722, entitled Laser Marking Apparatus, issued to Joseph J. Stone and Leroy V. Sutter, Jr. on Mar. 24, 1987, teaches a laser marker which includes a laser head which has a plurality of individual lasers each of which is dedicated to write a predetermined character row, mirrors and an exit lens. The laser marker writes columns in sequence as the article passes the laser head. The laser marker inscribes a matrix of a plurality of dot-craters to form alphanumeric characters and symbols onto moving articles. The matrix has a predetermined number of rows and columns which defines the alphanumeric characters and symbols. The laser marker may be adapted for use in a cable marking machine.
U.S. Pat. No. 3,434,456, entitled Machine for Circumferential Color Coding, issued to Chester J. Geating on Mar. 25, 1969, teaches a coding system which encodes an outer jacket of a cable. The coding system is operated by pulling the cable past successive marking stations which are phase displaced and in each of which is an ink carrier for marking the outer jacket. The coding system is a commercially available machine which applies footage and code marks to the outer jacket.
U.S. Pat. No. 4,579,759, entitled Inscribable Cable Marking Strip, issued to Manfred O. Breuers on Apr. 1, 1986, teaches a marking strip which is for use on an outer jacket of a cable. The marking strip includes a strip of an adhesive tape having a self-adhering bottom side and carrying an inscribable marking section. The beginning of the inscribable marking section is located at a distance from the adjacent front end of the adhesive tape to define an unlettered, transparent starting section of the strip which may be pressed onto the outer jacket without soiling the marking section or smudging the lettering applied to it.
U.S. Pat. No. 3,788,213, entitled Methods of and Apparatus for Marking Successive Sections of an Elongated Material, issued to William B. Brown, George Frank Besnyo and Eugene Marshall Hornor on Jan. 29, 1974, teaches an apparatus which applies a coding mark to successive sections of an outer jacket of a cable which are being advanced and in which the coding mark may be changed. The apparatus includes a first printer head and a second printer head. When the first printer head is in a printing alignment with the cable, it marks a code on the successive sections of the cable which is advanced in engagement therewith. When the second printer head is moved into printing alignment with the cable it marks a different code on successive sections of a subsequent cable which is of a different construction.
U.S. Pat. No. 2,739,528, entitled Wire Marking Apparatus, issued to James Lowe on Mar. 27, 1956, teaches a cable marking apparatus which includes a print wheel and a drive wheel which drives the print wheel independently of its contact with the cable, but at a peripheral velocity identical with the linear velocity of the cable. The drive wheel frictionally engages the cable at a point remote from the print wheel where the insulation is relatively hard and non-deformable. The print wheel prints on a cable which has an insulating coating and which is continuously moving. The print wheel lightly contacts the cable at a point where its insulating coating is still in a pliable and deformable state. Published German patent application number 1,465,840 also teaches a cable marking system.
U.S. Pat. No. 4,085,357, entitled Synchronous Switching Means for Operating Cable Marking Apparatus, issued to Chris Ansberg and Klaus Maisel on Apr. 18, 1978, teaches a cable marking machine which includes an uncoiler, a screw extruder and a marker, a cooling tube, a pull-off unit and a take-up reel. U.S. Pat. No. 3,552,308, entitled Synchronizing the Movement of First and Second Articles and Printing Markings on one of the Articles, issued to Robert F. Minehart on Jan. 5, 1971, teaches a cable marking machine which synchronizes the movement of an elongated jacketed cable and a rotatable print wheel. U.S. Pat. No. 2,867,00l, entitled Means and Method for Forming Indicia on the Surface of Continuous Vulcanized Products, issued to Edward Lewis, Willis D. Rice and Edward Estrin on Jan. 6, 1959, teaches a cable marking machine. U.S. Pat. No. 3,551,542, entitled Marking Method for Electric Cable, issued to Rosario K. Perrone on Dec. 29, 1970, teaches a method of forming and vulcanizing markings on the surface of an elongated extrudate. U.S. Pat. No. 4,182,239, entitled Cable and Hose Marking Machine, issued to Michael D. Timmins and Larry L. Trepanier on Jan. 8, 1980, teaches a cable marking machine which imprints identifying markings in an outer jacket of a cable which is plastic covered. U.S. Pat. No. 3,711,757, entitled Automatic Servo System for Electric Cable Marking Machines, issued to Jean Baptiste Marie Reforzo on Jan. 16, 1973, teaches a cable marking machine which includes a cable run measuring mechanism, a cable cutting mechanism and an electronic unit which generates marking control signals which change the pitch of the marking.